A video of two ingestible pills expanding in simulated gastric acid at 37o. The outside gelatin capsule dissolves during the first few minutes and the pill skin becomes hydrated. Hydration allows the compressed skin to unfold. The unfolding allows gastric acid to enter the balloon (capsule lumen). Gastric acid activates the production of CO2 and helps the skin to unfold further.
As gastric acid enters the balloon it hydrates and swells the hydrogel and causes the balloon to expand and become rigid. The complete process to the final rigid balloon shown at the end of the video takes approximately 24 hours.